UBI: Validate data_size

Make sure that data_size is less than LEB size.
Otherwise a handcrafted UBI image is able to trigger
an out of bounds memory access in ubi_compare_lebs().

Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: David Gstir <david@sigma-star.at>

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 5bbd1f094f4e33dca9c7ad3dca3edc7736b7e0bb..1fc23e48fe8e49fc947c972cca179399a60a37ec 100644 (file)
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -926,6 +926,11 @@ static int validate_vid_hdr(const struct ubi_device *ubi,
                goto bad;
        }
 
+       if (data_size > ubi->leb_size) {
+               ubi_err(ubi, "bad data_size");
+               goto bad;
+       }
+
        if (vol_type == UBI_VID_STATIC) {
                /*
                 * Although from high-level point of view static volumes may